MELBOURNE (Reuters) - Unseeded Briton Kyle Edmund bludgeoned his way to a shock 6-4 3-6 6-3 6-4 victory over third seed Grigor Dimitrov to reach the Australian Open semi-finals on Tuesday.

The South Africa-born 23-year-old, playing in his first grand slam quarter-final, showed no nerves as he blazed away with his fearsome forehand to subdue a jaded-looking Dimitrov.

Edmund crunched 46 winners to Dimitrov's 32 on a packed Rod Laver Arena sprinkled with vocal fans of both players.

There were nerves as Edmund served for victory but he held firm to become only the sixth British player to make a grand slam semi-final in the professional era.

Not only that but he began the tournament as the only British man in the draw after five-times Australian Open runner-up Andy Murray withdrew to have surgery on his injured hip.

Murray, recovering back at home, reacted to Edmund's achievement on Twitter. "Wow!" the Scot said.

Coached by Swede Fredrik Rosengren, who once worked with Magnus Norman and big-hitting Robin Soderling, Edmund produced nearly three hours of raw aggression on his first appearance on the Rod Laver showcourt.

His moment of victory was slightly delayed after a Hawkeye challenge confirmed Dimitrov's backhand was out.

"It's an amazing feeling, very happy," 49th-ranked Edmund, who will face sixth seed Marin Cilic in the last four, said on court.

He could even overtake Murray, Britain's number one since 2006, in the rankings if he gets to the final.

"I know what it feels like to be Andy Murray for the last eight years or however long," Edmund said of the spotlight now on him after his incredible run in Melbourne.

Dimitrov was heavy favourite after his superb fourth-round defeat of home favourite Nick Kyrgios but the portents were not good when he dropped serve in the opening game.

"Today was just one of those days, I just couldn't find a way," Dimitrov, still awaiting his first major final, said.

BLISTERING FOREHAND

The 26-year-old squared the match when Edmund misfired in the sixth game but the Briton thumped a blistering forehand winner off a weak second serve to grab a 5-4 lead.

Dimitrov had two break points and saved a set point in the next game but Edmund earned another chance with a volley and moved ahead with a heavy first serve.

Edmund dipped a little in the second set and Dimitrov took full advantage to level. But the silky Bulgarian never looked comfortable against an ultra aggressive opponent and a double-fault at 3-4 in the third set proved costly.

The players swapped breaks in the fourth but Dimitrov was winning only half his first-serve points and the pressure finally told as a backhand error gave Edmund a break at 4-4.

In a tense final game, Edmund double-faulted but an ace brought up match point before Dimitrov sliced long.

"I am loving it right now, just the way I'm playing," Edmund told reporters. "I'm 23 years old, my first grand slam semi-final. First time I played on one of the biggest courts in the world. To beat a quality of player like Grigor. They're great feelings."